The present invention provides a small, low power consumption ultrasonic flow
velocity meter. The burst signal generation section 110 generates two kinds
of burst signals with a phase difference and sends these burst signals to a pair
of transmission/reception ultrasonic transducers 6 and 7 located
on the upstream side and downstream side of the conduit to be measured 9. Upon
reception of the corresponding burst signals, the pair of the transmission/reception
ultrasonic transducers 6 and 7 convert the burst signals, send ultrasonic
waves with a phase difference to the conduit to be measured 9, receive the
ultrasonic wave sent by the other transmission/reception ultrasonic transducer
and propagated through the conduit to be measured and convert the ultrasonic waves
to received signals. These received signals are binarized through the binarization
circuits 16 and 17, exclusive-ORed by the exclusive-OR circuit 30
and converted to a phase difference signal indicating a phase difference and
the flow velocity of the conduit to be measured 9 is measured based on this
phase difference signal.
